Remove the Message Preview Pane
When you open Mail on Mac, by default, you see the Mail sidebar on the left of the Mail interface. (If you don’t see this sidebar, select Mailboxes on the Favorites bar, which is beneath the toolbar.) When you select a mailbox in the Mail sidebar, each email message in that mailbox appears in a list, including the message’s sender and subject, the date you received the email, and—depending on your settings—the first line or so of the email body. When you select an email in the messages list, the email opens in the message preview pane. To hide the message preview pane in Mail on Mac, select the vertical line that separates the list of messages from the message preview, then drag the line to the right until the message preview pane disappears.
Delete Emails Without Seeing Previews
To delete multiple emails from the messages list, select the message you want to delete, then press the Delete key.
Bring the Message Preview Pane Back
To bring the message preview pane back, hover at the far right edge of the Mail interface until the cursor changes to a left-pointing arrow. Select and drag left to reveal the message preview.
Why Disable the Preview Pane?
By default, Mail on Mac in Mac OS X and macOS displays email messages when you select an email in the message list. It also displays all the emails you select, even if you select messages for deletion. For privacy and security, however, you may not want previews of your emails. For example, opening a suspicious email may let the sender know that you opened it, confirming an active email address. Or, you don’t want others to see your messages.
